Add default filename for screenshot
Add default filename for screenshot

nathandunn/jbrowse,GMOD/jbrowse,nathandunn/jbrowse,nathandunn/jbrowse,nathandunn/jbrowse,GMOD/jbrowse,GMOD/jbrowse,GMOD/jbrowse,GMOD/jbrowse,nathandunn/jbrowse